Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:2.7.7.6 (RNA polymerase)
34,946 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Deletion and point mutants of T3 have been isolated and used to show that the early region of T3 DNA is organized in the same way as that of T7 DNA. Homologous early RNAs and proteins of the two phages have been identified by electrophoresis on polyacrylamide gels in the presence of sodium dodecyl sulfate. Both phages have five early mRNA's, numbered 0.3, 0.7, 1,1.1 and 1.3 from left to right, although no T3 protein that corresponds to the 1.1 protein of T7 has yet been identified. In general, corresponding early RNAs and proteins of the two phages migrate differently on gels, indicating that they differ in molecular weight and/or conformation. In both T7 and T3, gene 0.3 is responsible for overcoming the DNA restriction system of the host, gene 0.7 specifies a protein kinase, gene 1 specifies a phage-specific RNA polymerase, and gene 1.3 specifies a polynucleotide ligase. The 0.3 protein of T3 is responsible for the S-adenosylmethionine cleaving activity (SAMase) induced after T3 (but not T7) infection. However, cleaving of S-adenosylmethionine does not appear to be the primary mechanism by which T3 overcomes host restriction, since at least one mutant of T3 has lost the SAMase activity without losing the ability to overcome host restriction.
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PMID:SAMase gene of bacteriophage T3 is responsible for overcoming host restriction. 78 4

The rifampin-resistance mutation of LS3,an asporogenous mutant of Bacillus subtilis 3610, leads to altered mobility of the beta subunit of ribonucleic acid polymerase in sodium dodecyl sulfate-polyacrylamide slab gel electrophoresis. This finding argues that the rifampin-resistance mutation is located in the structural gene coding for the beta polypeptide.
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PMID:Rifampin resistance mutation of Bacillus subtilis altering the electrophoretic mobility of the beta subunit of ribonucleic acid polymerase. 80 57

Three peaks of DNA-dependent RNA polymerase (EC 2.7.7.6) activity were resolved when the enzyme was prepared from the isolated macronuclei of Tetrahymena pyriformis GL(amicronucleate strain) and chromatographed on DEAE-Sephadex A25. They were eluted at around 0.05, 0.15, and 0.2 M of ammonium sulfate, and termed TIa, TIb, and TII, respectively. All three enzymes transcribed heat-denatured DNA more efficiently, especially the peak TII, detecable only when heat-denatured DNA was used as a template. Further characterization of each enzyme, after they were rechromatographed on DEAE-Sephadex, demonstrated the similarity in many respects of TIa and TIb, and the distinct nature of the TII enzyme. TIa, TIb, and TII were all insensitive to rifampicin, while only TII was substantially inhibited by alpha-amanitin. On the other hand, the activity of TII was progressively lowered by increasing the concentration of ammonium sulfate in the assay mixture, a finding incompatible with those obtained thus far. It is concluded from the data that the Tetrahymena polymerase is of eukaryotic and not of bacterial type in spite of the findings indicating the bacterial nature of this organism.
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PMID:DNA-dependent RNA polymerase from a protozoan, Tetrahymena pyriformis. Extraction and partial characterization. 80 68

Nucleic acid-free extracts of Escherichia coli have been analyzed by chromatography on columns of cellulose, to which poly(A), poly(U), or poly(C) have been attached by ultraviolet irradiation. Proteins are released from the columns by stepwise elution with increasingly higher concentrations of salt, followed by washing with urea to remove very tightly bound molecules. The pattern of protein elution is reproducibly different for each of the homopolymer RNA-cellulose columns used: some proteins bind very tightly to one column, but poorly to others. Analysis by sodium dodecyl sulfate-polyacrylamide slab gel electrophoresis, by immunological cross-reactivity in double diffusion tests, and by enzymological assays, has allowed the identification of a number of these proteins. The RNA polymerase core enzyme binds to poly(C)- and to poly(U)-cellulose columns, and can be purified to 20 to 30 percent homogeneity in a single step. Ribosomal protein S1 and the termination factor rho bind very tightly to poly(C)-cellulose, and both can be purified to homogeneity rapidly, in much higher yields than previously reported. Poly(A)-cellulose chromatography allows the isolation of large amounts of an 80,000 molecular weight protein having an as yet unassigned cellular function. The host factor required for RNA phage Qbeta RNA replication in vitro can also be obtained from poly(A)-cellulose, and chromatography of extracts of phage Qbeta-infected E. coli on RNA-cellulose columns results in very rapid isolation of the Qbeta replicase enzyme. Homopolymer RNA-cellulose chromatography thus appears to be a simple, general technique, useful for the efficient isolation of a variety of RNA-binding proteins.
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PMID:Isolation of bacterial and phage proteins by homopolymer RNA-cellulose chromatography. 80 80

Antibody directed against rho factor from vegetative Bacillus subtilis was prepared by immunizing a rabbit with denaturated rho polypeptide isolated by electrophoresis of partially purified DNA-dependent RNA polymerase on a sodium dodecyl sulfate-polyacrylamide slab gel. Antiserum to rho reacted specifically with native rho polypeptide but not with core RNA polymerase as judged by complement fixation and by an immunodiffusion assay. Anti-rho antibody also inhibited the ability of rho to stimulate transcription of phage phie DNA but failed to inhibit transcription of poly(dA-dT) by core enzyme. Specific antibody was also raised against a mixture of the beta and beta' subunits of RNA polymerase purified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The effect of the anti-rho gamma-globulin on the transcription of phage phie DNA by RNA polymerase in crude extracts of vegetative and sporulating cells was examined. Anti-rho antibody markedly inhibited the transcription of phage DNA by RNA polymerase partially purified from vegetative bacteria by ammonium sulfate fractionation but had little effect on transcription of the phage DNA template by enzyme from sporulating cells. Addition of purified rho to a vegetative extract that had been depleted of rho by treatment with the anti-rho antibody restored active transcription of phage DNA. However, addition of purified rho to an antibody-treated extract of sporulating cells had little effect on phie RNA synthesis. These findings suggest that sporulating cells contain a component that interferes with the activity of the rho subunit of RNA polymerase.
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PMID:Antibody directed against Bacillus subtilis rho factor purified by sodium dodecyl sulfate slab gel electrophoresis. Effect on transcription by RNA polymerase in crude extracts of vegetative and sporulating cells. 81 Apr 88

The activities of RNA polymerases I and II have been measured in 3T6 during the transition from the resting to growing state by solubilization of the enzymes followed by chromatography on DEAE-Sephadex columns. The activity of RNA polymerase II remains unchanged during the first 12 h after serum stimulation while the activity of RNA polymerase I increases and closely parallels the increased activity seen in isolated nuclei. Compared to enzyme from resting cells. RNA polymerase I from serum stimulated cells elutes at a lower ammonium sulfate concentration on DEAE-Sephadex chromatography and its activity shows distinctly different dependencies on the concentration of ammonium sulfate and magnesium ion. These observations are discussed in relation to the possible mechanism by which 3T6 regulates the synthesis of preribosomal RNA.
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PMID:Solubilized DNA-dependent RNA polymerase activities in resting and growing fibroblast. 83 13

DNA-dependent RNA polymerases were extracted from rat uterine tissue, partially purified and resolved by DEAE-Sephadex chromatography. RNA polymerases I, II, IIIA, and IIIB eluted at the characteristic ammonium sulfate concentrations of 0.15, 0.28, 0.34, and 0.42 M, respectively. The sensitivity of each peak of polymerase to alpha-amanitin was examined and was shown to be essentially identical to the three classes of RNA polymerases in other mammalian systems. RNA polymerase I was insensitive to high levels of alpha-amanitin, RNA polymerase II was sensitive to low concentrations of alpha-amanitin (50% inhibition at 0.006 mug/ml) and RNA polymerases IIIA and IIIB were sensitive to high concentrations of alpha-amanitin (50% inhibition at 18 mug/ml). The alpha-amanitin sensitivity curve of total RNA synthesis measured in isolated nucleo demonstrated that the activity of each class of RNA polymerase could be quantitated in uterine nuclei. Thus the initial decrease in activity at low concentrations of alpha-amanitin (50% inhibition at 0.005 mug/ml) was attributed to the inhibition of RNA polymerase II activity, the second decrease in activity at higher concentrations of alpha-amanitin (50% inhibition at 15 mug/ml) was attributed to the inhibition of RNA polymerase III activity, and the activity which was resistant to the highest alpha-amanitin concentration tested was attributed to RNA polymerase I activity. When estradiol was given to immature rats 6 h before killing both RNA polymerases I and III levels in nuclei were increased significantly over the control values. The time course of these changes demonstrated that the increases in RNA polymerases I and III were first evident between 1.5 and 3 h following hormone treatment. Significantly, these increases in polymerase I and III in nuclei parallel the published increases for rRNA and tRNA synthesis following hormone treatment. However, the amount of RNA polymerase I and III was not altered upon extraction, suggesting that these changes are due to the alteration in chromatin template activity. Both estradiol and estriol produced identical increases in uterine RNA polymerase I and III 6 h after treatment.
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PMID:Hormonal control of transcription in the rat uterus. Stimulation of deoxyribonucleic acid-dependent RNA polymerase III by estradiol. 83 97

Partially purified rat liver RNA polymerase I chromatographed on ribosomal RNA-Sepharose loses most (96%) of its activity assayed on native calf-thymus DNA templates, but loses little (8%) of its activity assayed on poly(deoxycytidylic acid) template. Polymerase I is not stimulated by polymerase II protein factor, or by bovine serum albumin. However, it is stimulated by histones, polylysine, and spermine. Addition of a protein fraction eluted by high ionic strength from the rRNA-Sepharose also restores activity on native calf-thymus DNA. Further purification yields a fraction containing two proteins of 11 000 and 12 000 molecular weight. Both proteins are distinct from histones by electrophoresis in sodium dodecyl sulfate and in acid urea. Both proteins are basic, insensitive to heat, bind to DNA, and stimulate polymerase I activity. The degree of stimulation of polymerase I is dependent upon both the enzyme/DNA and the factor/DNA ratio. The protein factors also stimulate polymerase II activity about half as effectively as polymerase I.
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PMID:A protein cofactor that stimulates the activity of DNA-dependent RNA polymerase I on double-stranded DNA. 85 26

Three forms of RNA polymerase were assayed in nuclei and nucleoli isolated from rat liver and from Krebs II ascites cells. Assays of rat liver nuclei in the absence of exogenous DNA showed polymerase I accounted for 72% of the total activity, polymerase II for 17%, and polymerase III for 11%. The total activity in ascites nuclei was similar but the ratios of polymerase activities were different: polymerase I, 53%; polymerase II, 41%; and polymerase III, 6%. These values may reflect differences in the transcriptional activity of the nuclei. After isolation of nucleoli, both rat liver and ascites polymerase I accounted for 85% of enzyme activity. When exogenous calf-thymus DNA was added to nucleoli, there was a greater than 50% increase in activity suggesting that less than one-half of the polymerase I present was bound to endogenous template. Polymerase I was solubilized from either rat liver or ascites nucleoli by sonication at high ionic strength and subsequently purified by ion filtration, phosphocellulose, sucrose gradient centrifugation, and DNA-cellulose chromatography. The essentially homogenous ascites enzyme had a specific activity of 86 units/mg when assayed with native calf-thymus DNA and of 876 units/mg when assayed with poly(deoxycytidylic acid). Electrophoresis of the enzyme in sodium dodecyl sulfate indicated the presence of six subunits with molecular weights of 205 000, 125 000, 51 000, 44 000, 26 000 and 16 000. After the same purification procedure, the rat liver enzyme had a similar specific activity (98 units/mg) on native calf thymus and 362 units/mg on poly(deoxycytidylic acid).
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PMID:Purification of rat liver and mouse ascites DNA-dependent RNA polymerase I. 85 54

We have previously presented a rapid, high yield method for the large scale purification of homogeneous RNA polymerase II from wheat germ (Jendrisak, J.J., and Burgess, R.R.(1975), Biochemistry 14, 4639), and we now report a detailed study of its subunit structure. Polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate indicates that polypeptides with molecular weights of 220 000, 140 000, 40 000, 27 000, 25 000, 21 000, 20 000, 17 800, 17 000, 16 500, 16 000, and approximately 14 000 are associated with the enzyme. Two-dimensional polyacrylamide gel electrophoresis, by which the subunits were separated in the first dimension in the presence of 8 M urea at pH 8.7 and in the second dimension in the presence of 0.1% sodium dodecyl sulfate, indicates that the 40 000 molecular weight component is composed of two nearly identical polypeptides and that the low molecular weight components (smaller than or equal to 40 000) are acidic proteins except for the 25 000 molecular weight polypeptide.
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PMID:Studies of the subunit structure of wheat germ ribonucleic acid polymerase II. 85 83


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